Savings Bond Calculator
Sketch Series EE or Series I educational redemption value from purchase amount, rate, and years held. Choose compound (semi-annual style) or simple fixed interest — TreasuryDirect is the source of truth for actual values. Click any i for detail.
Bond inputs
Bond series
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Bond series
Series EE often uses a fixed rate with semi-annual compounding; Series I uses a composite rate that can change. This page is a rate sketch, not a Treasury redemption table. |
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Purchase amount ($)
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Purchase amount
What you paid (or current issue amount) for the bond. |
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Annual rate (%)
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Annual rate
Enter the fixed EE rate or an I-bond composite rate you want to model. Official rates come from Treasury. |
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Rate treatment
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Rate treatment
Compound applies the rate periodically (default twice per year). Fixed applies simple interest with no compounding. |
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Compounds per year
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Compounds per year
EE-style bonds typically compound interest semi-annually (2). Adjust only if you are stress-testing another schedule. |
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Years held
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Years held
How long you plan to hold before redeeming. Early redemption and interest penalties for very new bonds are not modeled. |
How to use this calculator
- Pick Series EE or Series I for labeling.
- Enter purchase amount and the annual rate you want to sketch.
- Choose compound (semi-annual default) or simple fixed interest.
- Set years held and compare the estimated value to TreasuryDirect before buying or redeeming.
Results explained
The headline is a modeled redemption value from your rate inputs — not a downloaded Treasury table. Compound mode mirrors the semi-annual accrual pattern many EE fixed-rate bonds use; fixed mode is a no-compounding sketch for quick comparisons.
Quick reference: savings bond sketch
Planning modes — confirm live rates on TreasuryDirect.
| Item | Detail |
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| Compound mode | FV = P × (1 + r/n)^(n×t) (default n = 2) |
| Fixed mode | FV = P × (1 + r × t) simple interest |
| EE 20-year note | Many EE bonds guarantee at least double at 20 years — not auto-applied here |
| Source of truth | TreasuryDirect redemption / rate tools |
For bank CD math, see the CD compound interest calculator or certificate of deposit APY calculator.
How the estimate is built
Compound: purchase × (1 + rate/n)^(n×years). Fixed: purchase × (1 + rate × years). Interest = value − purchase.
Example scenario
$1,000 at 2.7% compounded semi-annually for 10 years grows to roughly $1,308 — a planning sketch until you verify the exact Treasury redemption value.
FAQ
Is this an official Treasury value?
No. TreasuryDirect redemption calculators and published rates are the source of truth for Series EE and Series I bonds.
Compound vs fixed rate mode?
Compound mode applies your rate on a semi-annual (or custom) schedule like many EE fixed-rate bonds. Fixed mode is simple interest for a rough ceiling check.
Do EE bonds really double in 20 years?
Many EE bonds issued May 2005 or later carry a Treasury guarantee to at least double face value at 20 years if held — this tool does not enforce that guarantee; check your bond’s terms.
Series I rates change?
Yes. Series I composite rates reset; enter the rate you want to sketch, knowing actual accrual follows Treasury announcements.